Del, I unplugged the connector on the switch (located on the stat housing) and hey resto the fan doesn’t run. I’m going to put a test meter across it tonight, my understanding is that it should be an open circuit until the collant temp gets up to 84-90 degress C and which point the circuit is made and the fan will run. I’ve checked the fuse box and there’s two relays marked FAN, they’re both the same so I swapped them round and it made no difference. I’ll check them tonight to make sure they’re ok. I want oto be sure befoer I buy a new swictch as they’re £35 at the local motor factors and £65 at the dealers :(